112 | Great Geologists
Simplification of the sea-floor spreading hypothesis advanced by Harry Hess.
Support for Hess’s ideas was soon to appear when, in 1963, the British geologists, Fred Vine and Drummond Mathews,
published a paper in the journal Nature, noting that there was a symmetrical pattern of magnetic stripes (positive and
negative magnetic anomalies relating to magnetic pole reversals) on either side of the mid-ocean ridges. In addition, when
the basalts of the sea floor were dated, they were found to be the same age at similar distances away from the ridge on
each side. This suggested that the ocean floor was created at the mid-ocean ridges, and then progressively moved away
from the ridge, just as Hess had speculated.
Outside of his work on marine geology, Hess was also involved in many other scientific endeavours, including the Mohole
project (1957–1966), an investigation into the feasibility and techniques of deep sea drilling that eventually gave rise to the
Deep Sea Drilling Programme and its successors. He continued to be involved in the U.S. Naval Reserve, rising to the rank
of Rear Admiral. He was also an active adviser to U.S. governmental science programmes, including the Lunar Exploration
Missions. Hess died from a heart attack in Woods Hole, Massachusetts, on August 25, 1969, while chairing a meeting of
the Space Science Board of the National Academy of Sciences.
Hess was one of the truly great American geologists, who took full advantage of being at the center of the explosion of
data gathering from the marine realm in the mid-20th century. He had the rare ability to overturn his ideas when new data
demanded it and did not hesitate to say publically that he had been wrong. His greatest contribution to geology was the
notion of sea-floor spreading, without which the development of the paradigm of plate tectonics would have been delayed.
Hess said of himself in his speech accepting the Geological Society of America’s Penrose Medal in 1966, “As a geologist
who has often guessed wrong, I deeply appreciate the generosity of the society in balancing my errors against deductions
of mine not yet proven incorrect. I am pleased to come out with a positive balance.”
REFERENCES
This essay has drawn upon the following works:
Frankel, H.R. 2012. The Continental Drift Controversy, Volume III Introduction of Seafloor Spreading. Cambridge University Press,
476pp.
Lawrence, D.M. 2002. Upheaval from the Abyss. Rutgers University Press, 284pp.
Le Grand, H.E. 1988. Drifting Continents and Shifting Theories. Cambridge University Press. 313pp.
Oreskes, N. 1999. The Rejection of Continental Drift. Oxford University Press, 420pp.